The whole idea of a registry was to ease the minds of panicked parents so they would check the public registry, know that their lovely, upper-class neighborhood didn’t have any offenders in it, and go back to ignoring any talk of their kids being at risk for sexual abuse.
None of that has ever been true. As you read the story below, you’ll see that there are 25,000 offenders that law enforcement has completely lost track of, many of whom now live among poor communities where parents do not have the same resources that others do to keep their kids safe and have continued to offend.
What you also won’t see is that registries do nothing, absolutely nothing, to protect against offenders who haven’t been caught and convicted. That would be the vast majority of cases, by the way.